Definition - What does Field Symbol mean?
A field symbol (in SAP) is a mechanism in which applications are created with flexibility. As placeholders that do not reserve physical data field space but direct and point to its contents, field symbols are similar in concept to the dereferenced pointers of C language.
Field symbols are primarily used in Advanced Business Application Programming (ABAP) programs and provide great flexibility when addressing different data objects in ABAP. Additionally, they are useful when operating complex internal tables or changing related structure contents.
Techopedia explains Field Symbol
FIELD-SYMBOLS <FS> [<type>|STRUCTURE <s> DEFAULT <wa>].
In programs, field symbols are identified by angle brackets, which are part of the field symbol syntax. Field symbols may be created with or without type specifications. If the type is not declared, the field symbol inherits all technical characteristics of the assigned field. If the type is specified, the field symbol and data object type compatibility is checked in the ASSIGN statement.
Field symbols may point to any ABAP data object, which must be declared before assigning the field symbol to the same data object. In ABAP, there is no difference between successful field symbol assignments - whether the field is used or directly referenced. Data operations may be directly applied to the field symbols.
Field symbols may be used to solve program issues, which easily occur as the fields are assigned to field symbols at runtime, and syntax and security checks are limited by field symbol operations.